【作者】 赵晓莹；

【导师】 唐敏；

【作者基本信息】 西南财经大学 ， 会计学， 2009， 硕士

【摘要】 我国证券市场已经走过了18年的辉煌历程,随着我国证券市场的发展,近年来上市公司变更主审会计师事务所的现象日益普遍。据统计,沪深两市发生会计师事务所变更的A股上市公司由1998年的89家发展到2007年的145家,为了粉饰财务信息而变更会计师事务所的上市公司也逐渐增多。一个理性的投资者在得到上市公司变更会计师事务所的信息后,应该结合上市公司相关信息,分析上市公司变更会计师事务所是否存在潜在的不正当要求,对变更事件背后的真实目的和意图进行判断,考虑这种变更对自己的利益会产生怎样的影响,最后根据这些分析做出投资决策而进一步影响股价的变动,形成相应的市场反应。而我国广大投资者对上市公司变更会计师事务所这一事件的反应如何?他们是否洞悉隐藏在变更事件背后的动机,作出了适当的决策?这些问题引起笔者的研究兴趣。因此,本文以沪深两市2007年变更会计师事务所的A股上市公司为研究对象,研究上市公司变更会计师事务所的影响因素以及市场反应,以期能够帮助投资者充分利用信息,作出正确的决策;同时也希望能够帮助监管部门采取相应的措施,推动我国独立审计市场发展,规范证券市场运作。本文共分为五章,各章的内容简要介绍如下:第一章:绪论本章主要阐述本文研究背景和意义,简单介绍研究方法和研究内容,对会计师事务所变更的相关概念进行界定,同时归纳总结了国内外关于上市公司变更会计师事务所的动因和市场反应的研究。国外学者不仅研究会计师事务所变更动因,还积极研究会计师事务所变更的市场反应。而国内对于会计师事务所变更的研究在2000年以前还是一片空白,目前已有的研究主要集中在会计师事务所变更的动因上。第二章:上市公司变更会计师事务所的影响因素分析本章以2007年变更会计师事务所的145家A股上市公司为研究对象,分析我国上市公司变更会计师事务所的影响因素。首先对上市公司披露的有关信息进行统计分析,发现上市公司对变更会计师事务所的原因披露不充分,信息含量不足,广大股东无法获悉其变更会计师事务所的真实原因。然后对变更前审计报告意见类型、上市公司财务状况和前后任会计师事务所规模变化情况进行统计分析,得出以下几个结论:变更前被出具非标准审计意见的上市公司出于购买审计意见的目的,更倾向于变更会计师事务所;当上市公司处于财务困境时,管理当局为了达到粉饰报表、操纵利润的目的,更倾向于变更会计师事务所;会计师事务所规模不同也是上市公司变更会计师事务所的原因之一。第三章:会计师事务所变更市场反应的研究设计本章为研究设计部分,完成了研究假设的建立、研究方法和样本选择三方面的工作,为第四章的实证分析做铺垫。本章在第二章描述性统计分析的基础上,提出以财务困境、变更前审计报告意见类型、前后任会计师事务所规模变化方向和强制性变更为标准,对样本公司进行分组研究,并在此基础之上提出了本文的五个研究假设。本章还详细介绍了样本选取的过程和结果,对2007年发生会计师事务所变更的145家A股上市公司进行筛选,最终选定69例样本,并将这些样本分成了四个不同类型的组别。另外,详细的介绍事件研究法的步骤:首先要确定事件期,本文以董事会决议公告日和股东大会决议公告日为变更事件的基准日,以基准日前后5个交易日为研究事件期;然后估计超额收益率,本文先采用市场模型法估计预期收益率,再计算超额收益率、平均超额收益率和累计平均超额收益率;最后进行T检验,采用T检验统计方法来检验事件期内平均超额收益率和累计平均超额收益率是否显著不为零。第四章:实证检验及结果分析本章介绍运用SPSS 13.0软件和Microsoft Exce12003对样本公司主审会计师事务所变更事件的市场反应进行实证检验的过程,并对实证结果进行分析和解释。本文采用单样本T检验统计方法,分别对总体变更样本在两个事件期内的平均超额收益率和累计平均超额收益率进行检验,结果显示样本公司在股东大会决议公告日前后时窗内存在市场反应但不是十分显著,而在董事会决议公告日前后时窗内则不存在市场反应;采用配对样本的T检验统计方法,比较总体变更样本在两个事件期内的平均超额收益率和累计平均超额收益率,结果显示在股东大会决议公告日披露会计师事务所变更事件与董事会决议公告日相比具有一定的信息增量。运用独立样本T检验统计方法,分别对四个不同类型组别的样本公司在两个事件期内的平均超额收益率和累计平均超额收益率进行检验,研究结果主要包括:在董事会决议公告日前后时窗内不存在有差异的市场反应,而在股东大会决议公告日前后时窗内,市场对非强制性变更事件与强制性变更事件反应存在显著差异;在董事会决议公告日和股东大会决议公告日前后多个时段,市场对财务困境样本公司与非财务困境样本公司变更事件的反应存在差异,但这一差异在统计上并不显著;在董事会决议公告日和股东大会决议公告日前后时窗内,非标准审计意见变更样本公司市场反应为负,标准审计意见变更样本公司市场反应为正,但并不十分显著;在董事会决议公告日前后时窗内,市场对会计师事务所规模明显变小和会计师事务所规模明显变大的两组样本公司未作出存在显著差异的反应,而股东大会公告日前后时窗内,市场对会计师事务所规模明显变小的变更做出的反应为正,而对会计师事务所规模明显变大的变更做出的反应为负,这与理论分析恰好相反。第五章:研究结论与政策建议本章分析实证结果并未完全证实理论分析结果的原因,并提出相关政策性建议,同时指出本文在研究上的创新和不足之处。导致我国证券市场不能对变更事件作出显著反应的原因包括:(1)我国上市公司信息披露的有效性较低;(2)中小投资者投资行为具有较大的盲目性;(3)我国证券市场不规范,内幕消息众多,证券市场的退出机制根本不能体现市场竞争的优胜劣汰原则。并针对性地提出相关政策意见,从完善上市公司信息披露制度、提升投资者素质和加强证券市场监管三方面改进。与以往研究相比,本论文的研究角度和研究方法有所不同,主要体现在以下几个方面:(1)新的研究对象和数据:本文以2007年变更会计师事务所的上市公司为研究样本,采集的数据为2007年一年的,避免了跨期数据研究的不准确性。(2)作者在论文中借鉴了一些国际通用的研究方法,不仅采用普遍使用的单样本T检验和独立样本T检验研究上市公司变更会计师事务所的市场反应,而且采用了配对样本的T检验统计方法,研究在股东大会决议公告日披露会计师事务所变更事件相对于董事会决议公告日的信息增量。(3)为了可以合理确保某种股票的β系数在长期内稳定,从而提高市场模型的可靠性,选择200个交易日为估计期。本文研究上的存在一些缺陷和不足,有待以后研究改进:(1)本文样本量过小,使研究结果的代表性减弱,统计效果不强。(2)由于经验的不足及学识的有限,本文的影响因素主要借鉴以前学者的研究成果,采用描述性统计分析方法,未采用logistics回归分析方法进行检验,未能完全进行充分有效的科学分析。(3)由于一些影响因素的信息无法获得,难免遗漏可能存在而未被识别的潜在影响因素,导致研究未针对这些因素展开。(4)本文计算平均超额收益率和累计平均超额收益率所使用的β系数值,是以董事会决议公告日之前205个交易日到董事会决议公告日之前6个交易日为估计期计算而得的,而针对股东大会决议公告日的研究并未重新选择估计期再次计算β系数。在以后的研究中,可考虑选择两个估计期分别计算β系数。更多还原

【Abstract】 China’s stock market has gone through 18 years of glorious history. As the rapid development of securities market in China, the accounting firms’switches become a common phenomenon increasingly. According to the statistics, the accounting firms’switches occurred in A-Share listed companies by the development of 89 in 1998 to 145 in 2007. In order to whitewash financial information, more and more listed companies change the accounting firm. Rational investors should be combined with the relevant information, analyze the existence of potential improper demands for changes, and judge the real purpose behind the affair, when they know that a listed company has switched the accounting firm. On the basis of these analyses, rational investors make a final investment decision-making further change in price and form the appropriate response to the market.In China, what is the response of the majority of the investors to this incident? Are they aware of the hidden motive behind the incident and make the appropriate decision? These problems arise from the author’s interest in the study. Therefore, this paper chooses the A-share listed companies switched the accounting firms in Shanghai and Shenzhen stock markets in 2007 for the study, and researchers the reasons and the impacts of the market to the affair. In order to be able to help investors see through the motive behind the act of the accounting firms’switches, to reduce their own disadvantage asymmetric, and to reduce some market risks the decision-making process; At the same time, I hope to find some laws and useful information for the regulatory authorities to take appropriate measures, to provide some help to promote the development of the independent audit market, regulate the operation of the securities market.This article is divided into five chapters, the brief contents of each chapter is as follows:Chapter I: Introduction This chapter studies the background and significance of this paper, summarizes the research methods and contents, and defines the concept relating to the accounting firms’switches. Summarize the research achievements home and abroad as a starting point for this paper. Accounting literature on accounting firms’switches were well documented in developed countries. The Domestic research on the accounting firms’changes began the year of 2000, and mow the studies focused on the motivation of the accounting firms’changes research. Based on the current researches, the author plans to discuss the characteristics determinants and the market reactions in China.ChapterⅡ: The studies on the factors of the listed companies switched accounting firmsIn order to study the factors on the accounting firms’switches, this chapter chooses the A-share listed companies switched the accounting firms in Shanghai and Shenzhen stock markets in 2007 for the study. Firstly, summarize the disclosures information of the listed companies. The author discovered that the disclosures information of the listed companies does not fully disclose the real motivations, so the majority of their shareholders can not know the real reasons. Then, on the based of the statistics description, the author analyzes the main real reasons of China’s listed companies to change accounting firms, including the type of audit reports, financial situation and accountants firms’the size.ChapterⅢ: The designs of studies for the market reactions on the accounting firms’switchesThis chapter is the part for the empirical designs, including three areas of making the research assumptions of this article, the methods and the steps of the process, and the sample selection. It is the basis on the fourth chapter. This chapter bases on the second chapter, divides the sample companies into three gropes by the standards, such as financial difficulties, the type of the audit report before the switches, and the size of the accounting firms, and studies the sample companies respectively. Also this article studies the steps of the event study methodology in detail: including the events day, the case study period, cumulative abnormal return, and cumulative average abnormal return, then the author interprets the T-test. T test is used to test cumulative abnormal return, and cumulative average abnormal return is significantly non-zero. ChapterⅣ: Empirical test and result analyzingThis chapter introduces the use of SPSS 13.0 software and Microsoft Exce12003 samples for the events of empirical research testing process and results of empirical analysis and interpretation to the market reactions on the accounting firms’switches.Using the single sample T-test method calculates the value of AAR and CAR of the total samples, and tests the market reactions on the event of the accounting firms’switches. Using the paired sample T-test method calculates the value of AAR and CAR of the group of the changing and no changing. Using the independent sample T-test method calculates the value of AAR and CAR of the groups of financial difficulties switches, modified audit opinion switches, the accounting firms’level difference switches and the compulsory selection, in order to test the market reactions on the different groups.ChapterⅤ: Research conclusions and policy suggestionsFinally, the author researches the relative information disclosure system and other law systems, and found some shortcomings, such as the low effectiveness of the disclose information, the lack of substantive information, the information disclosed in the form of non-standard and information time lag, and the investors are "childish" and "ignorance". At the end of this article,several policy proposals are brought forward on the above researches. Put forward the views of relevant policies, improve the information disclosure system of listed companies, enhance the quality of the investors, and strengthen the supervision of securities market in order to improve the cognitive ability of the events of the accounting firms’switches, and give an appropriate response.Because of inadequate knowledge of the author, however, this study has many limitations. This will motivate the author to conduct further research.更多还原